R contains data, stored in the R variable sleep, which show the effect of two soporific drugs, namely the increase in hours of sleep compared to control. Create a boxplot for both groups using the command boxplot(sleep[[1]] ∼ sleep[[2]]) and speculate about whether comparing 20% trimmed means will give a result similar to Welch’s test. Use the R command z=fac2list(sleep[,1],sleep[,2]) to separate the data into two groups and use the function yuen to check your answer.